The context of the invention is that of a naval vessel intended to deploy a towed submersible object. In such a context, in the non-operational phase, the submersible body is stored onboard the vessel and the tractor or towing rope is wound on the drum of a winch. Conversely, in the operational phase, the submersible body is submerged behind the boat and pulled by the latter by means of the tractor rope, the rope itself being immersed apart from the end that remains linked to the winch.
In such a context, it is useful to reduce the drag of the tractor rope when the latter is immersed. To do this, it is known to use a streamlined rope and in particular a rope streamlined by means of fairings, or scales, such as that illustrated by FIG. 1. This scale comprises an elongate element, hydrodynamic, for example, in the form of a fin, presenting on a thick internal edge a tubular duct into which passes the rope and a thin external edge allowing a less turbulent flow of the water about the rope. The set of scales totally or partially covers the rope.
In normal operation, the scales are mounted to move about the rope and joined to rotate relative to each other. This way, the rotation of one scale leads to a rotation of the adjacent scales and, step by step, of all of the scales.
This means that, both when the rope is deployed in the water and when it is wound on the drum, the scales are all oriented in the same way and any change of orientation of one of the scales will bit by bit affect all the scales streamlining the rope. Thus, when the rope is deployed at sea, the scales are naturally oriented in the direction of the current generated by the pulling force exerted by the movement of the vessel. In the same way, when the rope is wound onto the drum of the winch, as the rope rises, all the scales adopt one and the same orientation relative to the drum, as illustrated by FIG. 2, an orientation that makes it possible to wind the rope by maintaining the scales parallel to each other turn-by-turn.
However, it is often the case that, during the life of the rope, the link between certain scales is broken and that one or more scales is/are partially damaged. In this case, with the link between scales being broken in certain places, it is possible that one or more scales will no longer be aligned with the whole. It is then in particular possible that, when the rope is wound onto the drum of the winch, one or more scales will be badly oriented relative to the drum and that they will then not adopt a position conforming to the arrangement presented in FIG. 2, an arrangement in which all the scales situated at the same level on the drum are parallel to each other. One or more scales can thus, for example, be lying down in a configuration such as that illustrated by FIG. 4. The consequence of such a positioning is to hamper the winding of the tractor rope and often, as illustrated by the figure, to lead to the breaking of the badly-positioned scale.